Rotary sprinklers of the impact type are well known in the art and in the patent literature. Exemplary sprinklers of this type are described and claimed in U.S. Pat. Nos. 4,402,460 and 4,760,959, which are assigned to the assignee of the present application, and in U.S. Pat. No. 4,632,312.
Impact drive sprinklers often include apparatus for selectably limiting the azimuth of sprinkler coverage and cooperating apparatus for changing the mode of operation and direction of rotation of the sprinkler at the selected azimuthal boundaries. Normally such apparatus comprises multiple parts, including a spring, and usually must be assembled by hand.